The Galaxy S3, Samsung’s flagship smartphone, will replace the old school dial-tone phone to help the manager in the dugout speak with pitching coaches in the bullpen.

But don’t expect managers to start walking around the field or inside the clubhouse blabbering on the Galaxy — a special T-Mobile network set up in stadiums uses geofencing that keeps the phones from operating outside the dugout and bullpen.

“Unlike a typical sponsorship, we’re approaching this partnership as a collaboration in which T-Mobile, MLB and MLBAM will work together to evolve the game with exciting new technology innovation enhancing the experience for customers and fans,” T-Mobile CMO Mike Sievert said in a press release.

That encrypted network will be custom-built by T-Mobile for MLB stadiums around the country. It’s called On-Field Communication System, which can’t be disrupted by other wireless users in the stadium because of the encryption.

T-Mobile, which is headquartered in Bellevue, also appears to be taking over the MLB from a sponsorship point of view. First of all, the network will “enhance and broaden network” within select stadiums.” I know it’s always annoying to have your cell phone slow down considerably when you get inside a packed stadium.

T-Mobile will also work with MLB’s media leg to help bolster the official league mobile app, and that’s not all. T-Mobile will sponsor ESPN’s Wednesday Night Baseball and is partnering with several national broadcast partners like FOX and Turner. The company also has additional sponsor initiatives with ESPN’s Baseball Tonight Show. Finally, all those “dugout calls” during the game will now be sponsored by T-Mobile.

The wireless system will be tested at the World Baseball Classic in Arizona in March. After careful assessments, the system will roll out to the rest of the MLB. The Seattle Mariners and Pittsburgh Pirates are currently sponsored by T-Mobile.

Taylor Soper is a GeekWire staff reporter who covers a wide variety of tech assignments, including emerging startups in Seattle and Portland, the sharing economy and the intersection of technology and sports. Follow him @taylor_soper and email taylor@geekwire.com.